Retractable blade knife



FIG. 1 is a side perspective view of the retractable blade knife, showing the new design;

FIG. 2 is a front view of the retractable blade knife;

FIG. 3 is a rear view of the retractable blade knife;

FIG. 4 is a side view of the retractable blade knife;

FIG. 5 is another side view of the retractable blade knife;

FIG. 6 is a top view of the retractable blade knife; and,

FIG. 7 is a bottom view of the retractable blade knife. 

The ornamental design for a retractable blade knife, as shown and described. 